I have a 1989 Yamaha 70hp 2 stroke. I was on the water and had it at WOT. Seemed to run pretty good but would miss every now and then. It started missing more and more but then I noticed that while trimming up or down the rpm would go up. It started to stumble pretty bad so I headed for the launch. That’s when I realized that if I trimmed all the way down and just held the trim button in it would run perfect. The second I released the trim button it would stumble again. I had to hold the trim down the whole way back as it was pretty bad. I’m lost as to what would cause this.
